COMUNICA CIONES Rev. Bio!. Tr op., 30(2): 171-173, 1982

Habitatof cruenta () in coastal sand dunes oí Marica,Brazil

Luiz Drude de Lacerda* and John DuVall Hay** Departamento de Ecologia, Universidade Federal do Rio de Janeiro, I1ha da Cídade Universitaria, Río de Janeiro, R.J., 21941

(Received for publication March 25 , 1982)

Resmren: Se realizó un estudio de los habitats utilizados por N. cruenta (R. Graham) L. Sínith en un ecosistema costero de dunas de arena en Barra de Maricá, Rio de Janeiro. Los resultados demuestran que esta especie tiene la capacidad de mantener una élevada densidad en ambientes normalmente adversos, atravésde epifitismo facultativo.

The family Bromeliaceae is widespread c omposition and horizontal and vertical throughout the Neotropics. It is subdivided into structure (see Hay and Lacerda, 1980 fo r a thre e subfamilies distinguished by floral and complete descrtption). The study was done in seed morphology (Smith and Downs, 1974). the two intermediar'}' zones 2 and 3. Once in However, it can also be subdivided into �Íle other extreme zones, communities are ecological groups basedon mechanisrns of water herbaceous, thus precluding the possibility of and nutrient absorption (Pittendrigh, 1948). epiphytic habitats. Zone 2 ig located in the The types of habitats used by different valley behind the primary dunes and exhibits a of bromeliads are many (pittendrigh, 1948, clumped plant distribution (± 1 - 2 m in height, Aragao , 1967; Medina, 1974). One aspect coverage ± 25%). It gradualIy gives way to Zone of habitat use in the Bromeliaceae is 3 which is denser, fe aturing srnaller and few er facultative epiphytism, present in each of open areas (± 6-7 m in height, coverage > 75%). the subfamilies (Medina 1974). These transitions occur within 300 m. The present study deals with habitat use by Habitat use by N. cruenta was quantified Neoregelia cruenta (R. Graham) L. Smith in the using a line-intercept technique. Two line Barra de Maricá, a coastal sand dune ecosystem, transects, perpendicular to the ocean and the approximately 35 km E of Rio de Janeiro, vegetation zones, were established in Zones 2 Brazil (220 57' S, 430 08' W). The local and 3. All individuals of N. cruenta within 2 m bromeliad flora consists of N. cruenta, Bromelia of each transect were counted and their habitat antiacan tha Bertol, Tillandsia spp. and recorded. Specifically, we noted if the Aechmea sp .. Of these only N. cruenta exploits individual was associated with another species, both terrestrial and epiphytic habitats. This and if so, whether it was growing as an species is one of the dominants in this system epiphyte An individual was considered to be (Lacerda and Hay 1977) anrl important in associated if it was within 15 cm of at least one improving soil chemistry (Hay and Lacerda other species, and classified as epiphytic when 1980; Hay et al. , 1981). no part was in contact with the soil surface . The area studied can be divided into fo ur Neoregelia cruenta can be found in all zones distinct zones, with increasing distance fr om of the Barra de Maricá, but it is most abundant the ocean, based on differences in plant species in Zones 2 and 3 where it attains a similar

* Present address : Instituto de Biof{sica, Universidade Federal do Rio de Janeiro, llha da Cidade Universitária' Rio de Janeiro, RJ, 21941.

** Present address: Departamento de BiologiaVegetal, Universidade de Brasilia, Brasília, D.F. 70919.

171 1 72 REVISTA DE BIOLOGIA TROPICAL

Fig. 1. Group of terrestrial individuals of Neoregelil1 Zone 2, while in Fig. 3 it is present within the cruenta in the open areas of the second vegetation tree canopy in Zone 3. When N. cruenta was zone of the Barra de Maricá (RJ). Epiphytic forms are present in Zone 3 as a terrestrial, it occurred on also present in the background, along with the third the periphery of the closed communities or vegetation zone. within the open areas. The results of this study are shown in Table Fig. 2. Epiphytic forms of N. cruenta in the second vegetation zone of the Barra de Maricá (RJ). 1. A total of 222 individuals of N. cruenta were encountered in Zone 2 and 298 in Zone 3. A comparison (Dixon and Massey 1968) of the Fig. 3. Epiphytic form of N. cruenta in the canopy of percentages of the total number of the third vegeta'tion zone of the Barra de Maricá (RJ). associated and of the epiphytes showed that in both cases Zone 3 was significantly different density of approximately 86 individuals/100 from Zone 2; z = 2.63 (p < 0.01) fo r the 2 m (Lacerda and Hay 1977). This maintainance percentage of plants associated and z = 2.32 . of density with a change in habitats appears to (p < 0.01) for the percentage of epiphytes, be accomplished through epiphytism since supporting our hypothesis that the degree insufficient open ground remains to support an of epiphytism increased between the second equiva1ent number of terrestrial individuals. and thrid zone<. Typical habitat use by N. cruenta in Zones 2 A possible advantage fo r fa cultative and 3 is shown in Figs. 1,2,3. Figure 1 shows a epiphytism would be reduced competition for group of individuals of N. cruenta in the open light. Light has been shown by Pittendri� areas of Zone 2. Figures 2 and 3 show examples (1948), Veloso and Klein (1957) and Aragao of the use of the epiphytic habitat. In Fig. 2 N (1967) to be important in determining cruenta is epiphytic on a community group in bromeliad distribution in ecosystems. Being a COMUNICA CIONES 173

TABLE 1 Chavarría and an anonymous reviewer for their constructive criticism of the manuscript. Comparison 01 rhe percentage o[ Neoregelia cruentain Barra de Maricá (R. J.) The figures in parentheses refer fa the percentage ofthe rubtotal LITERATURE CITED

ZONE 2 ZONE 3 Nwnber % Number % Aragao , M. B. Considerayoes de habitat e

Associated distribui�o geográfica de algunas Bromeliáceas. Terrestrial 92 (92) 138 (81 .6) Sellowia, 19: 83-95. Epiphytic 8( 8) 31(18.4) Subtotal lOO 45.05 169 56.71 Dixon, W.J., & F.J. Massey. 1968. lntroduction of Not �sociated statistical analysis. McGraw-Hill, New York. Terrestrial 122 54.95 129 43.29 Total: 222 100.00 298 100.00 Hay, J.D., & L.D. de Lacerda. 1980. Alterayoes nas características do solo após a fixa�io de Neoregelia '.'tank" bromeliad, N. cruenta is independent of cruenta (R. Graham) L. Smith em'. um ec ossistema the soil and receives nutrients ann water from de dunas de areia. Cienc. e Cult, 32: 863-867. atmospheric sources. It is also po�sible to Hay , J.D., L.D. de Laeerda, & A.L. Tan. 1981. Soil speculate on the evolutionary historY of the eation inerease in a tropical sand dune eeosystem Bromeliaceae. In this fam ily , the obligatory due to a terrestrial bromeliad. 'Eeology , 62: epiphytes are considered to be the most highly 1392-1395. evolved (Smith and Downs 1974); thus the capability for farultative epiphytism might Lacerda, L.D. de & J.D. Hay, 1977. Importancia de algumas espécies '{e getais perenp.s em um represent a transitory phase in the evolutionary ecossistema de dunas de areia. Cien. e Cult. (Supl. , history of the family. . Resumos), 29: 491492. In summary, observations on habitat use by Medina, E., 1974. Dark C0 fixation, habitat N. cruenta show that it is capable of 2 exp loitation of different habitats within the preference and evolution within the Bromeliaceae, Evolution, 28: 677-{i86. coastal sand dune ecosystem. The mechanism used is facultative epiphytism, possibly in Pittendrigh , C., 1948. The bromeliad-anopheles­ response to a requirement of high light malaria eomplex in Trinidad. I. The bromeliad intensity for germination or growth. flora. Evolution, 2: 58-89.

Smith, L.B. & R.J. Downs, 1974. Flora Neotropica. ACKNOWLEDGEMENTS Monograph NO.14 (Piteairnioidae). Hafner Press, New York. We thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico Veloso, H.P., &R.M. Klein, 1957. As comunidades e (CNPq) for support (grants 107410/79 to LDL associa�oes vegetais de mata pluvial do sul do Brasil. I. As comunidades do Município de and 2222. 1915/78 to JDH) of this project. We Brusque, Estado de Santa Catarina. Sellowia, 8: also thank Drs. D. Benzing, J. Utley, M. 81-235.